Club 80-90 Forums

Evening all.

I’m pondering a few options for the future.

Scenario is I have a 5 speed gearbox ( I think ABN or ABM from memory ) and it runs around 3k revs at 60mph. ( Maybe a tad over )
First gear is almost pointless, whereas second is a bit too low a gear to use for pulling away from a standstill.

I keep checking gear ratios on the RJES site, and scratching my head a little.

Thinking into the medium distance future where I was planning to get the gearbox refurbed to extend its lifespan, I started thinking about gearing, and whether there is a benefit to altering it for better motorway usage.

The 5 speeds look to have differences for second, fifth, and final drive ratios only, and they look like the last gear for 4 and 5 speeds are fairly similar ( within the same ratio spectrums - for example around 0.82 to 0.85 for 5th gear. )

So…. The question is, do I find a 4 speed to refurb, re-gear and thus negate the pointless first gear, or stick 5 speed and refurb and re-gear to keep whatever benefit there is to the additional gears for hills? :lol:  

Come on chaps. Long shot I know, but looking for some experience to tell me what you find ‘best’ if you have had examples of multiple boxes.

For context, it’s a weekend van with rock and roll bed but no wood interior, and I do have all of the 4 speed linkage already in the garage somewhere. ( Long story - when I bought it years ago the 5 speed box was paired with a 4 speed linkage and housing lol )

Here is the matrix I’m looking at:

https://rjes.com/vw-bus-manual-gearbox-types/

Aidan will be your man there id have thought.
The AAP box i have was really great for cruising til it jammed I. 2nd. Could do 70 at around 3700 on the rev counter ish give or take. The current unknown one I got in 50mph is about my limit as them im going over 4k at 60 let alone 70.

I think all 5 speeds 1st is always a very short gear.

So if you have a 2.1 which version (DJ or MV) and how fuelled (carb/injection), how timed, and what fuel (Supermarket E10, Premium E5, LPG ?) are you running

ABN is 4.83 final drive, standard 2nd and 0.82 fifth
ABM is same gearing but with LSD

Both originally 1.9 boxes

ASM was also fitted to 1.9s and has the 4.57 final drive, but with the 0.85 fifth cos the 1.9 has slightly less grunt than the 2.1s - so knowing exactly what you have is important, easy to make a box with same or similar gearing as AAP if you have a 4.57 final drive, ASM has the taller 2nd gear which is even worse for pulling away in from a halt

Body type, tin top, hi-top, pickup, with or without front spoiler

Final question is what size tyres do you run/plan on running long term

VW used a proper overdrive 5th (0.765) in the 83-84 era when they could fuel the engine at revs without worrying about emissions but the change to real world testing meant they had to be more conservative with 5th gear and back off the fuelling from 1985 (that's the same regs they, and everyone else, were cheating in the 2000s with ECUs that recognised when they were being tested and ran cleaner than irwe)

I've got a 1.6d with a very short 4 speed box. 1st almost useless, 2nd too short for a normal roundabout and 4th too short for the motorway.

I ended up putting 4.7% bigger tires on, that solved all my issues.

I now have a blown head(gasket) so it might have overloaded the engine a bit.

Aidan wrote: ↑26 Jul 2026, 14:14 So if you have a 2.1 which version (DJ or MV) and how fuelled (carb/injection), how timed, and what fuel (Supermarket E10, Premium E5, LPG ?) are you running

ABN is 4.83 final drive, standard 2nd and 0.82 fifth
ABM is same gearing but with LSD

Both originally 1.9 boxes

ASM was also fitted to 1.9s and has the 4.57 final drive, but with the 0.85 fifth cos the 1.9 has slightly less grunt than the 2.1s - so knowing exactly what you have is important, easy to make a box with same or similar gearing as AAP if you have a 4.57 final drive, ASM has the taller 2nd gear which is even worse for pulling away in from a halt

Body type, tin top, hi-top, pickup, with or without front spoiler

Final question is what size tyres do you run/plan on running long term

VW used a proper overdrive 5th (0.765) in the 83-84 era when they could fuel the engine at revs without worrying about emissions but the change to real world testing meant they had to be more conservative with 5th gear and back off the fuelling from 1985 (that's the same regs they, and everyone else, were cheating in the 2000s with ECUs that recognised when they were being tested and ran cleaner than irwe)

Cheers Aidan.

It’s a DJ running on Pierburg carb, I have a westfalia poptop roof on it, no front spoiler.
The wheels and tyres are 225/50 R17 and I have had them years - don't foresee changing them any time soon.

I definitely feel it needs better motorway travel, and I suppose a better final drive would help in some way to make 5th better.

Still unsure whether the better option is to find a 4 speed to refurb and then switch it all over. 


 

5 speed with 4.57 final drive gives you a taller 1st gear, as taller in all gears, keeps the 3 intermediate gears which are closer together for easier driving and should be more economical than building a 4 speed with the same final gear which will be gappier, though petrol engines are ok with the gaps cos they rev but if you don't like revving it then not ideal. Whatever you build in a 4 speed it won't be the same as a modern high torque close ratio vehicle, the 5 speed is the closest to that compromise hence VW generally fitted the AAP to 2.1s designed for distance work and passenger carrying

The wide tyres mean more rolling drag, and load on the steering when turning compared to the stock ones but better able to lay down (the limited) power without wheel spin

Sounds like Steve has an ABR (or similar) which is originally n/a diesel box meant for 50hp engines which were meant to be local delivery vehicles not mile munching motorway cruisers, so quick through the gears, nice around town, but restricted top speed at bearable revs

Aidan wrote: ↑27 Jul 2026, 06:19 5 speed with 4.57 final drive gives you a taller 1st gear, as taller in all gears, keeps the 3 intermediate gears which are closer together for easier driving and should be more economical than building a 4 speed with the same final gear which will be gappier, though petrol engines are ok with the gaps cos they rev but if you don't like revving it then not ideal. Whatever you build in a 4 speed it won't be the same as a modern high torque close ratio vehicle, the 5 speed is the closest to that compromise hence VW generally fitted the AAP to 2.1s designed for distance work and passenger carrying

The wide tyres mean more rolling drag, and load on the steering when turning compared to the stock ones but better able to lay down (the limited) power without wheel spin

Sounds like Steve has an ABR (or similar) which is originally n/a diesel box meant for 50hp engines which were meant to be local delivery vehicles not mile munching motorway cruisers, so quick through the gears, nice around town, but restricted top speed at bearable revs

Thanks again Aidan.

Makes sense. Assuming AAP is the preferable end goal, could my ABN/ABM ( or any 5 speed with 2.33 geared second gear ) be reconditioned and have the final drive changed at the same time to 4.57? ( as all other ratios are the same in the two it would seem. ) 

I’m not there yet and thinking it’s a ‘next year’ consideration, but it is good for me to get a clear path through in my mind.

as 'Churchill' would say

Oh yes

crown and pinion set

Aidan wrote: ↑27 Jul 2026, 08:03 as 'Churchill' would say

Oh yes

crown and pinion set

Top man, Aidan.

Muchas gracias.